Feeding facilities (a/k/a feedlots or feed yards) are critical to the world's food supply, but managing them efficiently presents many challenges. For example, upon arrival at a typical cattle feedlot, each member of the herd will make at least one trip through a chute, where handlers can typically afford to spend only about 45-seconds processing each calf. Initial processing typically involves some variation of each of the following: (1) standard treatment such as spraying, deworming, and whatever type of basic treatment is being administered to the entire herd; (2) when feasible, some level of assessment and any special treatment that may be indicated based on the assessment; and (3) identification by attaching either an RFID ear tag, a numbered or bar-coded ear tag, or some other form of individual animal identification. Other processing activities can include vaccination, castration, horn-tipping, weighing, etc., all of which can help in managing the herd. Naturally, whatever processing takes place, records also need to be created, updated and transferred for each calf being processed.
Challenges arise from the need for speed while it is so difficult to determine what particular type of treatment is needed for each individual calf. Yet, when a feedlot omits a critical treatment, it can lose a big part of the herd . . . fast. So, rather than attempt to predict which calves need treatments and which do not, the industry is constantly facing temptations to mass treat all animals entering their lot as a precaution. Mass antibiotic treatment of an entire herd of ‘at risk’ cattle is not only expensive, but it presents a litany of concerns for beef quality and microbial mutation. Regulatory agencies (e.g., FDA) strongly discourage overuse of antibiotics in order to minimize the risk of microbial mutation, practically outlawing Gentamicin Sulphate and blended cocktail treatments for use in bovine applications. Plus, while most consumers would rather consume pure organic beef cattle with fewer additives, there has long been a huge need to improve herd processing through more accurate assessments and more intelligent treatments.
Other herd management practices have been advancing more systematically than livestock assessment techniques, particularly in the area of livestock tagging. Tags applied to each calf are used to identify the particular calf and are typically applied in the ear where they can be readily seen and tracked. Radio Frequency Identification (“RFID”) technology is being utilized to a greater extent in the agricultural industry. More and more historical data is being required by regulatory agencies before a calf can be slaughtered or packed.
At least one other company has attempted to help ranchers manage cattle based on temperature, but its attempt has been less than ideal. Tekvet [website: tekvet.com] has launched a system of mobile temperature monitors (mounted in the calves' ears) which link to a base station. It is an object of the present invention to improve over such prior attempts, providing a system that provides a more accurate temperature measurement that is more consistently reliable, and more cost effective than a surface-based thermistor mounted in the ear.
Core temperature, the internal body temperature, or more precisely the temperature of the blood as it flows in or near the pulmonary artery near the heart, would be even more ideal. Unfortunately, core temperature has been difficult to measure accurately without invasive placement in the sensitive interior of the body. Such measurements have long required a surgically invasive insertion of a temperature probe, which is impractical for use in feedlots. In practice, core temperature is not really measured but is approximated with rectal, oral and ear thermometers and others. A better, more accurate and more rapid non-invasive measurement of actual core temperature is needed for use in the field.
In the United States' cattle industry, annual mortality of cattle due to disease is estimated to be in the hundreds of millions of dollars. A reliable method of determining the health of a calf or the presence of disease is by assessing the body temperature of the animal. In the case of infections, environmental factors, or toxins, a calf's temperature will elevate. These elevations are diagnostic to veterinarians in the diagnosis of disease and disease conditions in cattle. In the day-to-day production of cattle, the evaluation of the presence of increased body temperature or fever is under utilized due to time constraints and the need to physically restrain the animal. This under utilization of temperature evaluation delays the diagnosis of disease and therefore increases the ineffective uses of medications and loss of animals.
Traditionally, to obtain temperature measurements, clinical thermometers have been inserted rectally or orally and must remain in position for periods of as long as several minutes to obtain a stable reading. This usually requires restraint of the animal, which is time consuming and labor intensive. Typically, the body temperature of cattle is measured with a clinical mercury Fahrenheit thermometer or with a digital thermometer. A mercury thermometer has a scale ranging from 94 F. to 110 F. and each degree is divided into ⅕ths. The thermometer requires shaking the mercury column into the bulb end. The thermometer is then lubricated or moistened and manually inserted its full length into the rectum. It remains in the rectum for a minimum of 3 minutes to obtain an accurate reading. As most animals object to this procedure, the animal must be physically restrained during this time.
In recent years, temperature sensors of low thermal mass, such as miniature thermocouples or thermistors, have been used with an electronic digital readout to make the more rapid digital thermometers. However, these devices still require oral or rectal insertion and restraint of the animal but the time for accurate measurement is reduced to one minute.
Other approaches to animal temperature measurement are based on sensing the thermal emission energy, the so called black body emission. This energy is emitted as a wide band electromagnetic spectrum by all heated bodies and has a wavelength distribution and intensity in proportion to temperature. This emitted energy is detected by use of a non-contact microwave, millimeter (mm) wave, or infrared (IR) sensors. Thermal emission measurement is rapid, but the accuracy by which the thermal emission is related to temperature is affected by two factors, in addition to instrumental errors, if any. The first factor is how accurately an emitting surface that is accessible for measurement relates to the core temperature. This frequently poses a problem in that skin may not be a true representation of the internal temperature. This is particularly a problem with Infrared (IR), where the depth within a body from which the emission is detected is very shallow and is essentially proportional to the outer temperature of the skin. The second factor, surface emissivity, also affects the amount of thermal emission from a body at a given temperature. This causes temperature measurements, based on thermal emissions, to vary depending on the color and the physical properties of the materials being measured. To attempt to overcome this source of error, some IR thermal emission thermometers use a probe inserted into the ear. However, surface emissivity in the ear can vary due to the amounts and types of debris and these can limit the accuracy. In another variation, an insert is placed in the ear of the animals to provide a constant emissivity target for the IR sensor. The insert must be in the ear for a sufficient time to reach thermal equilibrium prior to measurement, which is undesirable from cost and time considerations.
The possibility of measuring the core temperature of cattle by remote (hands-off) sensing has been of great interest over the past thirty years or more. Previous approaches have been based on (1) passive detection of the magnitude of the IR or microwave energy that is emitted in proportion to the temperature and wavelength (in accordance with Planck's law) from most materials including human or animal hide or ear (interior); (2) the use of implants and/or tags which use contact type thermal sensors (thermistors, thermocouples, etc.) and usually a wireless means of reading out the data on demand; and (3) the use of ingested temperature sensing capsules which contain a temperature sensor and a radio frequency (VHF or UHF) transmitter or transponder to communicate the temperature data from the interior of the animal to an outside read out unit. None of these previous devices or approaches is completely satisfactory due to cost, poor accuracy, practical application limitations, or other reasons.
Existing passive IR emission thermometers are of limited accuracy (+/−one degree or worse). These methods are based on sensing surface (skin or hide) temperature and do not have sufficient accuracy nor repeatable for direct measurement of animal body temperature. Skin temperature is not always an accurate indication of the internal temperature of the animal. Also, the emissivity of hair-covered skin is variable and, with IR, will not provide accurate skin temperature nor core temperature indications.